Percentile analysis

Percentile Analysis:

Click <perc> to enable the percentile analysis.

Click <go> or press the Enter key to start the actual measurement.

Click <go> again or press the ESC key to interrupt or cancel the measurement.

Figure 62: Percentile analysis option window

Selection window options (Figure 62):

Signal type
Input level
Lead time: time before the measurement starts
Measuring time: relevant only in the setting for one-time
Click <Turn on signal 2> to enable Signal 2.

Present a second signal to the loudspeaker (or several speakers for real ear).
When Signal 2 is enabled, the signal type and level may be adjusted.

The measurement will appear on the screen after it is completed. Selected curves can be edited by clicking: <insert>, <hide>, or <delete>.

For further information, please refer to the section: "Display and administrate curves."

Various display modes in the percentile analysis:

Settings for the display modes are located in the Presentation tab.

Figure 63a: 3 values model

Figure 63b: 3 values model

Figure 64a: 4 values model

Figure 64b: 4 values model

Figure 65a: 5 values model

Figure 66a: Display of diagram targets, dynamic compression rates (CR), and the target curve transformation

Figure 66b: Display of the diagram targets (red), the dynamic CR (numerical values at the percentile bars) and the target curve transformation (black line).

Figure 67a: Display at lines

Figure 67b: Display at lines

Percentile analysis measuring options:

Figure 68: Percentile analysis window

Table refers to Figure 68.

Setting	Description
Signal Type	Select the signal type. Signal types include: Speech Natural signals Technical signals (e.g. CHIRP)
Input Level	Select the input level. If the desired level is not available on the drop-down menu, manually enter the value in the field.
Modulation Frequency and Modulation Depth	An amplitude modulation may be selected for the signal types: CHIRP, white noise, pink noise, speech simulated noise, or pure tone. Can be used to determine dynamic compression rates in hearing aids.
Lead Time	Time between when the measurement is enabled and the actual start of the measurement. The actual start of the measurement is delayed. Lead Time only applies when performing a single measurement and when the hearing aid has long attack times.
Measuring Time	Only applies when performing a single measurement.
Enable Signal 2	Add a second signal to the actual measuring signal. May be used to analyze noise reduction algorithms in hearing aids or to test directional microphones (only available in real ear).
Signal 2 – Signal Type	Identical to “Signal Type” above.
Signal 2 – Level	Identical to “Input Level” above.
Signal 2 to Loudspeaker	Only enabled in real ear. It is possible to present a second signal from a different direction, provided that the corresponding loudspeaker is activated and connected.
Start	Starts the actual measurement.
Abort	Measurement does not start

Calibration of percentile analysis:

Performed of the available signals and refers to the total long-term level (RMS value).
Performed separately for the test box and real ear depending on your selection: <HIT> or <REM>.

To determine if calibration is necessary, observe the total level of the reference micrphone during the calibration meaurement (Figure 69). This value should match the level adjusted by the user. If this is not correct, calibration should be performed of the signals that are being used. Otherwise, it will take 15 minutes to calibrate all available signals.

Figure 69: Calibrating the percentile analysis

Selection of the signals for calibration:

The ACAM System estimates the amount of time necessary for calibration and displays an approximate value. Figure 70 shows an estimated time of 1 minute.

In this window, you can click on the box to select and deselect signals to be calibrated. Click the <start calibration> button to begin the calibration.

Figure 71: Selection of signals for calibration

Own Files:

Click the button <own files> to include user files into the percentile analysis.
Click the button <choose new data> to select a file (must be a .wav file).
Please remember to calibrate the signal prior to use for an actual measurement.

Figure 72: Own Files window

Adjustments in Setup:

The measuring accuracy/measuring speed of the percentile analysis can be adjusted in the setup window of the Measure tab.

Select from the following resolutions:

Resolution	Number of measuring points (Defaults)
Very good	500 Measurements
Good	200 Measurements
Medium	100 Measurements
Fast	40 Measurements
Very fast	20 Measurements

Note:

Fewer measurements: results in a faster test time. Recommended for adjusting hearing aids as changes are displayed more quickly.
More measurements: results in a more accurate measurement. To perform an accurate analysis, more measurements are necessary.